JP3628348B2 - Power circuit - Google Patents

Description

[0001]
[Industrial application fields]
The present invention relates to a power circuit including a plurality of power circuits, and more particularly to a DC / DC converter including a plurality of DC / DC conversion circuits.
[0002]
[Prior art]
Many attempts have been made to obtain effects such as higher speed and larger capacity by connecting a plurality of circuits in parallel and appropriately controlling the operation of each circuit. For example, a circuit is known in which a plurality of DC / DC conversion circuits are connected in parallel, and the output of each DC / DC conversion circuit is averaged to extract a large-capacity DC voltage.
[0003]
The DC / DC converter is desired to have a high conversion efficiency with little loss during conversion, but a resonance type DC / DC converter is known as one form for realizing the high efficiency. The configuration and operation of a resonant DC / DC converter connected in parallel as a large capacity and high efficiency DC / DC converter will be described below.
[0004]
FIG. 5 is a circuit diagram of a DC / DC converter in which five resonant DC / DC conversion circuits are connected in parallel. In the figure, the first resonance type DC / DC converter circuit (hereinafter, abbreviated as a first DC / DC), the switch SW1 is provided between the input-side DC power supply and the inductor _{L 11,} the inductor _{L 11} the output of which is connected to the anode of the diode D _11. With the cathode of the diode _{D 11} is connected to the inductor _{L 12,} it is grounded via a capacitor _{C 1} and diode _{D 21.} Then, the LC resonance by the inductor _{L 11} and capacitor _{C 1.}
[0005]
The second to fifth resonance type DC / DC conversion circuits (hereinafter abbreviated as second to fifth DC / DC, respectively) have the same configuration as the first DC / DC. Then, the output side of the inductor _L 21 _{~L 25} of the first to fifth DC / DC is in the common output is connected to one another. Common output is grounded via the capacitor C _0.
[0006]
Next, the operation of the resonant DC / DC converter having the above configuration will be described. First, when the switch SW1 in the ON state, the current supplied through the inductor L ₁₁ from the input-side DC power stored in the capacitor C _1, the potential rises. Thereafter, when the switch SW1 in the OFF state, the charge accumulated in the capacitor C ₁ is not able to flow back to the inductor L ₁₁ because it is blocked by the diode D _11, it is consumed as the output voltage, gradually its potential It goes down.
[0007]
The above operation is the same in the second to fifth DC / DC. Then, the outputs of the first to fifth DC / DCs are averaged by a filter composed of inductors L _{21 to} L ₂₅ and a capacitor C ₀ and output as a DC voltage.
[0008]
[Problems to be solved by the invention]
By the way, in order to simplify the control of the switching operations of the first to fifth DC / DC switches SW1 to SW5, the DC voltage is not applied even if the switches SW1 to SW5 are controlled to be turned on simultaneously. Can be obtained. However, when a voltage waveform with the same phase is output from the first to fifth DC / DC, the ripple of the output waveform increases, and the capacitance of the filter capacitor for smoothing must be increased. Occurs.
[0009]
In order to solve this problem, for example, it is conceivable to control the switching states of the switches SW1 to SW5 at the timing shown in FIG. That is, in the example shown in the figure, one cycle is set to 12.5 μsec, the on-state time of each switch SW1 to SW5 is set to 4 μsec, and the switches SW1 to SW1 in the order of the switches SW1, SW2, SW3, SW4, SW5, and SW1 Control 5 is turned on. Then, a period (1.5 μsec in this example) where a period in which an arbitrary switch is turned on and an on-state period in which the switch is turned on at the next timing of the arbitrary switch is provided is always provided. Control is performed so that at least one switch is turned on. As described above, by providing a period in which the ON state of the two switches overlaps as described above, the output voltage of the resonant DC / DC converter connected in parallel becomes continuous, so that the ripple is absorbed on the output side. Therefore, the burden on the filter is reduced, and it is possible to reduce the size of the capacitor and suppress the heat generation of the capacitor.
[0010]
However, in general, there is a demand for downsizing the entire configuration of the DC / DC converter, and for this purpose, the first to fifth DC / DCs are designed as close as possible to each other. If there is a period in which the switches are turned on at the same time, the two DC / DC conversion circuits whose operations are controlled by these two switches influence each other. For example, when the switches SW1 and SW2 are turned on at the same time, the magnetic flux generated by the inductor _{L 11} and _{L 12} mutually interfere with each other, since the they inductor _{L 11} and _{L 12} is trance attached, they inductor L waveform of the current flowing through the ₁₁ and _{L 12} is disturbed. The waveform of the current flowing through the inductors L ₁₁ and L ₁₂ will be described with reference to FIG.
[0011]
In FIG. 7, the waveforms of the currents I _R1 and I _R2 flowing in the inductors L ₁₁ and L ₁₂ when it is assumed that there is no interaction between the first and second DC / DC are indicated by solid lines. In this case, the waveforms of the currents I _R1 and I _R2 are half sine waves.
[0012]
However, in practice, as indicated by a broken line in the figure, the falling of the half sine wave of the current I _R1 becomes gentle, and the rising of the half sine wave of the current I _R2 also becomes gentle. For this reason, a switching loss occurs and the electric power converted into heat increases. Therefore, in order to obtain a desired voltage as the DC / DC converter, there is a problem that the input current is increased and the conversion efficiency is deteriorated.
[0013]
Such a problem is not limited to the resonant DC / DC converters connected in parallel, but a configuration in which a plurality of circuits are arranged close to each other and the influence of the operation state of these circuits extends to adjacent circuits. Must be considered.
[0014]
The present invention has been made to solve the above-described problems, and an object of the present invention is to reduce the interaction between circuits in a power circuit composed of a plurality of power circuits.
[0015]
[Means for Solving the Problems]
Power circuit according to claim 1 of the present invention, each equipped with five or more power circuit including the inductance element, so as to always be at least one of the on-state among those five or more of the power circuits, they The configuration is such that five or more power circuits are switched, and at the time of switching, the on-state periods of the two or more power circuits are controlled to overlap each other. Then, the power circuits adjacent to each other among the five or more power circuits operate so as not to be turned on at the same time.
[0016]
According to a second aspect of the present invention, there is provided a power circuit including five or more power circuits and control circuits each including an inductance element, and the control circuit controls an on / off state of the five or more power circuits. Therefore, at least one of the five or more power circuits is always in an on state. When the control circuit switches the five or more power circuits and controls the ON state periods of the two or more power circuits to overlap each other at the time of switching, the five or more power circuits Are controlled so as not to simultaneously turn on power circuits adjacent to each other.
[0017]
According to a third aspect of the present invention, there is provided a power circuit including five or more power circuits and control circuits each including an inductance element and arranged in a predetermined order, and the control circuit includes the five or more power circuits . By controlling the on / off state of the power circuit, at least one of the five or more power circuits is always in the on state. The control circuit is configured to turn on a first power circuit among the five or more power circuits for a first period and straddle at least one off-state power circuit from the first power circuit. The second power circuit arranged in the second period is controlled to be in an on state for a second period partially overlapping with the first period.
[0018]
In the power circuit, a shielding plate that magnetically shields the five or more power circuits from each other may be provided. Further, each of the five or more power circuits may be a DC / DC conversion circuit.
[0019]
In the first to fourth aspects, a DC / DC converter is configured by configuring each of the plurality of power circuits as a DC / DC conversion circuit.
[0020]
The power circuit of the present invention is configured such that two or more power circuits are controlled so that the on-state periods of two or more power circuits overlap each other while switching five or more power circuits. Since the on-state is not turned on, the interaction generated when the adjacent power circuits are turned on at the same time while obtaining continuous output power is reduced.
[0021]
【Example】
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a circuit diagram of a resonant DC / DC converter of an embodiment of a power circuit according to the present invention. In the figure, the same reference numerals as those used in FIG. 5 described as the prior art indicate the same elements. Further, in FIG. 1, capacitors C _{11 to} C ₁₅ are provided on the input side of the first to fifth resonance type DC / DC conversion circuits (hereinafter abbreviated as first to fifth DC / DC, respectively). However, these capacitors C _{11 to} C ₁₅ are omitted in FIG. Therefore, the circuit configuration of the resonant DC / DC converter shown in FIG. 1 is as described with reference to FIG. 5 and is omitted here. Moreover, 1st-5th DC / DC respond | corresponds to the some power circuit as described in each claim here.
[0022]
The resonant DC / DC converter is configured by electrically connecting the first to fifth DC / DCs in parallel, but their physical arrangement is in the order of their numbers (1, 2, 3, 4, 5).
[0023]
The operations of the first to fifth DC / DC are the same as those described with reference to FIG. 5, and the switches SW1 to SW5 are turned on for 4 μsec every 12.5 μsec. Controlled. This control is executed by the control circuit shown in FIG.
[0024]
FIG. 2 is a control circuit for controlling the on / off states of the switches SW1 to SW5 of the resonant DC / DC converter. The counter 10 is a Johnson counter with a built-in decoder function. Each time a clock signal is input, the counter 10 cyclically pulses in the order of output 1 → output 2 → output 3 → output 4 → output 5 → output 1. Output. Here, the period of the clock input to the counter 10 is 2.5 μsec.
[0025]
Pulse signals output from the outputs 1 to 5 of the counter 10 are input to the pulse width adjusting circuits 11-1 to 11-5, respectively. The pulse width adjusting circuits 11-1 to 11-5 are, for example, one-shot multivibrators, and output a signal having a pulse width of 4 μs at the rising (or falling) timing of the input pulse signal.
[0026]
The signals output from the pulse width adjustment circuits 11-1 to 11-5 control the switches SW1, SW4, SW2, SW5, and SW3, respectively. When the switches SW1 to SW5 are transistors, signals output from the pulse width adjustment circuits 11-1 to 11-5 are input to the bases of the transistors. With this signal, each of the switches SW1 to SW5 repeats an on state of 4 μsec and an off state of 8.5 μsec in a 12.5 μsec cycle.
[0027]
FIG. 3 is a time chart for explaining the on / off states of the switches SW1 to SW5. As shown in the figure, when the on / off state of each of the switches SW1 to SW5 is controlled by the signal output from the control circuit, the switch having the on-state period overlapping the on-state period of the switch SW1 is the switch SW3. And a switch SW4. Hereinafter, the expression that the corresponding first to fifth DC / DCs are in the on state when the switches SW1 to SW5 are in the on state is used.
[0028]
Here, the first DC / DC and the third DC / DC are not adjacent to each other, and the first DC / DC and the fourth DC / DC are not adjacent to each other. Accordingly, the first and third DC / DCs (or the first and fourth DC / DCs) are simultaneously turned on, and the inductors L ₁₁ and L ₁₃ (or the inductors L ₁₁ and L ₁₄ ) are simultaneously turned on, respectively. Even when a current flows, the inductors are separated by a predetermined distance or more (at least a distance that crosses over one DC / DC conversion circuit), so the mutual influence due to the magnetic flux generated by these inductors is very small. .
[0029]
For this reason, the waveform of the current flowing through the inductors L ₁₁ and L ₁₃ (or the inductor L ₁₄ ) during the period in which the switches SW1 and SW3 (or the switch SW4) are on is substantially a sine half wave, and the switching loss is reduced. The efficiency of DC / DC conversion is improved.
[0030]
Similarly, in each of the second to fifth DC / DCs, another DC / DC conversion circuit that is turned on so as to overlap with any DC / DC conversion circuit in a period in which it is turned on. Is a DC / DC conversion circuit that is not adjacent to the arbitrary DC / DC conversion circuit. Therefore, when the on / off state of each of the switches SW1 to SW5 is controlled using the signal output from the control circuit, at least one DC / DC conversion circuit among the first to fifth DC / DCs is turned on. The DC / DC conversion circuits adjacent to each other can be operated so as not to be turned on at the same time. As a result, the switching loss is reduced in each of the first to fifth DC / DCs, and the efficiency of the DC / DC conversion is improved in the entire resonant DC / DC converter.
[0031]
The connection relationship between the pulse width adjusting circuits 11-1 to 11-5 and the switches SW1 to SW5 is not limited to the pattern shown in FIG. 2, and the DC / DC conversion circuits adjacent to each other are simultaneously turned on. For example, the outputs of the pulse width adjustment circuits 11-1 to 11-5 may be input to the switches SW1, SW3, SW5, SW2, and SW4, respectively.
[0032]
In the above embodiment, the five DC / DC conversion circuits are connected in parallel. However, the number of DC / DC conversion circuits may be any number as long as the number is five or more.
[0033]
In the above-described embodiment, the switching timing is controlled to prevent an interaction when a current flows simultaneously in the inductor of the adjacent DC / DC conversion circuit. As another configuration, FIG. As shown, a method using a shielding plate is conceivable. In this case, the shielding plate 20 is resonated so that the magnetic flux generated when a current flows through each of the inductors L _{11 to} L ₁₅ does not reach the other inductors so that the inductors L _{11 to} L ₁₅ are shielded from each other. It attaches to the board | substrate 21 in which the type | mold DC / DC converter is formed. The shielding plate 20 is, for example, a silicon steel plate. Also in this configuration, the interaction between the inductors L _{11 to} L ₁₅ can be reduced.
[0034]
Returning to FIG. Capacitors C _{11 to} C ₁₅ temporarily store electric charges to be supplied to the first to fifth DC / DC, respectively. For example, in the first DC / DC, the charge in the capacitor C ₁₁ is accumulated the potential rises when the switch SW1 is turned off. Then, the switch SW1 is turned on when the charge flows through the inductor L _11. At this time, if the switches SW1 and SW2 are turned on at the same time, since the short wiring between the capacitor _{C 11} and _{C 12,} mutually affect the potential of the capacitor _{C 11} and _{C 12} to each other, the inductor _{L 11} or there is a possibility that current is disturbed flowing to L _12. However, in the resonance type DC / DC converter of this embodiment, since adjacent DC / DC conversion circuits are not simultaneously turned on, such a problem does not occur, and each of the inductors L _{11 to} L ₁₅ is not connected. The current flowing therethrough is stable, and stable DC / DC conversion can be performed.
[0035]
Further, the effect of controlling the switching timing as described above also appears for the filter. In the example of FIG. 1, the interaction between the inductors L _{21 to} L ₂₅ is reduced by the above control, and stable smoothing can be expected. In this case, the plurality of filters each including the inductors L _{21 to} L ₂₅ correspond to a plurality of power circuits in each claim.
[0036]
As described above, the timing control of the on / off states of the switches SW1 to SW5 as described above not only prevents the interaction of the inductors of the adjacent DC / DC conversion circuits, but also causes the adjacent circuits to be simultaneously turned on. It is effective in preventing the interaction generated by. In other words, an integrated circuit in which a plurality of circuits are arranged side by side and at least one of the circuits is always in an on state (operating state), and adjacent circuits are simultaneously in an on state. In the configuration that generates the interaction, the timing control shown in the above embodiment is effective for reducing the interaction.
[0037]
【The invention's effect】
In a power circuit composed of a plurality of power circuits, the adjacent power circuits are prevented from being turned on at the same time, so that the interaction between the power circuits can be reduced.
[0038]
In particular, in a DC / DC converter configured by connecting a plurality of DC / DC conversion circuits, the adjacent DC / DC conversion circuits are prevented from being turned on at the same time. Since the interaction between the inductors is reduced and the switching loss is reduced, the conversion efficiency is improved.
[Brief description of the drawings]
FIG. 1 is a circuit diagram of a DC / DC converter of an example of the present invention.
FIG. 2 is a block diagram of a control circuit that controls the switching operation of the DC / DC converter.
FIG. 3 is a time chart for explaining the operation of each DC / DC conversion circuit of the DC / DC converter.
FIG. 4 is a schematic diagram showing a shielding plate provided between each DC / DC conversion circuit of the DC / DC converter of the present invention.
FIG. 5 is a circuit diagram showing an example of a DC / DC converter in which a plurality of DC / DC conversion circuits are connected in parallel.
FIG. 6 is a time chart for explaining the operation of each DC / DC conversion circuit in the prior art.
FIG. 7 is a diagram for explaining disturbance of a current waveform in the prior art.
[Explanation of symbols]
SW1~SW5 switch _L 11 _{~L 15} inductor (resonance)
D ₁₁ to D ₁₅ diodes _C 1 -C ₅ capacitor (resonant)
D _{21 to} D ₂₅ Diode L _{21 to} L ₂₅ Inductor C ₀ Capacitor C _{11 to} C ₁₅ Capacitor 10 Counter 11-1 to 11-5 Pulse width adjustment circuit 20 Shielding plate

Claims (5)

Each includes five or more power circuit including the inductance element, so as to always be at least one of the on-state among those five or more of the power circuit, while switching them five or more of the power circuits and at the time of switching In a power circuit that is controlled so that the on-state periods of two or more power circuits overlap each other,
A power circuit characterized in that power circuits adjacent to each other among the five or more power circuits are not simultaneously turned on. Each includes five or more power and control circuits including the inductance element, by the control circuit controls the on and off states of the five or more of the power circuits, always among those five or more power circuit In a power circuit in which at least one of is turned on,
When the control circuit switches between the five or more power circuits and controls the on-state periods of the two or more power circuits to overlap each other at the time of the switching, the control circuit includes the five or more power circuits. A power circuit, wherein power circuits adjacent to each other are controlled so as not to be turned on simultaneously. Each including five or more power circuits and control circuits arranged in a predetermined order including inductance elements, and the control circuit controls on / off states of the five or more power circuits, In a power circuit in which at least one of the five or more power circuits is always on,
The control circuit is configured to turn on a first power circuit among the five or more power circuits for a first period, and to dispose at least one off-state power circuit from the first power circuit. The power circuit is controlled to turn on the second power circuit that is turned on for a second period that partially overlaps the first period. 4. The power circuit according to claim 1, 2 or 3, further comprising a shielding plate that magnetically shields the five or more power circuits from each other. 5. The power circuit according to claim 1, wherein the five or more power circuits are each a DC / DC conversion circuit.

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